DE102016119586A1 - DIAGNOSIS OXIDATION CATALYST DEVICE WITH HYDROCARBON STORAGE - Google Patents

Abstract

A method for diagnosing an oxidation catalyst (OC) device of an exhaust aftertreatment system is provided. The method monitors a differential temperature throughout the OC device. The method determines if the differential temperature has a temperature rise. The method determines that the OC device is functioning properly in response to determining that the differential temperature is experiencing a temperature rise.

Description

FIELD OF THE INVENTION

The subject matter of the disclosure relates to the diagnosis of an exhaust aftertreatment system, more specifically, the diagnosis of an oxidation catalyst (OC) device of an exhaust aftertreatment system.

BACKGROUND

Manufacturers of internal combustion engines, in particular diesel engines, are faced with the demanding task of meeting the current and future emission standards for the release of nitrogen oxides, in particular nitrogen monoxide, as well as unburned and partially oxidized hydrocarbon, carbon monoxide, particulate matter, and other particles. To reduce emissions from internal combustion engines, an exhaust aftertreatment system is used to convert some or all of the exhaust components to unregulated exhaust components and to reduce the soot particles of the exhaust gases flowing out of the engine.

An exhaust aftertreatment system typically includes one or more treatment devices, such as e.g. Oxidation Catalyst (OC) devices, selective catalytic reduction devices, particulate matter filters, mixing elements, and urea / fuel injection nozzles. Some emission standards require that these components of an exhaust aftertreatment system, in particular an OC device, be separately diagnosed. For this reason, a diagnostic scheme is desirable for diagnosing an OC device.

BRIEF SUMMARY OF THE INVENTION

In an exemplary embodiment of the disclosure, a method for diagnosing an oxidation catalyst (OC) device of an exhaust aftertreatment system is provided. The method monitors a differential temperature throughout the OC device. The method determines if the differential temperature has a temperature rise. The method determines that the OC device is functioning properly in response to determining that the differential temperature is experiencing a temperature rise.

In another exemplary embodiment of the invention, a diagnostic system is provided. The diagnostic system includes an oxidation catalyst (OC) device disposed in an exhaust aftertreatment system of a vehicle. The diagnostic system further includes a control module. The control module serves to monitor a differential temperature throughout the OC device. The control module also serves to determine if the differential temperature has a temperature rise. The control module also serves to determine that the OC device is functioning properly in response to determining that the differential temperature has experienced a temperature rise.

In another exemplary embodiment of the invention, an exhaust aftertreatment system is provided for an engine of a vehicle. The exhaust aftertreatment system includes an oxidation catalyst (OC) device disposed in an exhaust aftertreatment system, a first temperature sensor disposed above the OC device, a second temperature sensor disposed below the OC device, and a control module. The control module is operative to detect a differential temperature throughout the OC device based on the temperatures sensed by the first and second temperature sensors. The control module also serves to determine if the differential temperature has a temperature rise. The control module also serves to determine that the OC device is functioning properly in response to determining that the differential temperature has experienced a temperature rise.

The above features and advantages, as well as other features and advantages of the invention, will be readily apparent from the following detailed description of the invention, as well as the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, advantages and details appear in the following detailed description of the embodiments and the detailed description given by way of example only, with reference to the following drawings, in which:

1 FIG. 10 is a functional block diagram of a vehicle having an exhaust aftertreatment system according to exemplary embodiments; FIG.

2 a data flow diagram for illustrating a control of the exhaust aftertreatment system 1 according to the exemplary embodiments;

3 Figure 12 shows several diagrams illustrating different temperature difference profiles according to the exemplary embodiments;

4 FIG. 4 is a diagram illustrating various temperature difference profiles according to the exemplary embodiments; FIG. and

5 FIG. 3 shows a flowchart illustrating a method that may be performed in accordance with the exemplary embodiments. FIG.

DESCRIPTION OF THE EMBODIMENTS

The following description is merely exemplary in nature and is not intended to limit the present invention in its applications or uses. It should be noted that in all drawings the same reference numbers refer to the same or corresponding parts and features.

The term "module" as used herein refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated or group processor) and a memory containing one or more software or firmware programs, a combinatorial logic circuit and / or other suitable components that provide described functionality. When implemented in software, a module may be formed in memory as a non-transitory computer-readable storage medium that can be read by a processing circuit and stores instructions that are executed by the processing circuitry to perform a method.

According to an exemplary embodiment of the invention shows 1 an exhaust aftertreatment system 10 for the reduction of regulated exhaust components of an internal combustion engine 12 such as the engine of a vehicle 32 or engines used in various non-vehicle applications. As you can see, it can be at the engine 12 to handle any type of engine, including a diesel engine, a gasoline engine, a homogeneous compression ignition engine, or any other type of engine.

The exhaust aftertreatment system 10 generally includes one or more exhaust pipes 16 , as well as one or more exhaust aftertreatment devices. In various embodiments, the exhaust aftertreatment devices may include an oxidation catalyst (OC) device 14 , a selective catalytic reduction (SCR) device 18 , a fine dust filter (PF) 20 , as well as a hydrocarbon (HC) injection nozzle 30 and / or other treatment devices (not shown).

The exhaust pipes 16 transport exhaust gases 15 from the engine 12 in the various exhaust aftertreatment devices of the exhaust aftertreatment system 10 , The exhaust 15 flows through the exhaust aftertreatment system to remove or reduce particulate matter 10 and then released into the atmosphere.

The OC device 14 may include a flow-through metal or a monolithic ceramic substrate wrapped in a mat or other suitable substrate that expands when heated to protect and isolate the substrate. The substrate may be packaged in a stainless steel canister or housing that has an inlet and an outlet in fluid communication with exhaust pipes or ducts. An oxidation catalyst compound can be applied as a washcoat and platinum group metals, such as. Platinum (Pt), palladium (Pd), rhodium (Rh) or other suitable oxidation catalysts which function efficiently and treat unburned, gaseous and non-volatile hydrocarbons (HC) and carbon monoxide (CO) which are oxidized to carbon dioxide (CO ₂ ) and water (H ₂ O) to form. The OC device 14 also oxidizes part of the nitrogen oxide (NO) to nitrogen dioxide (NO ₂ ). The OC device 14 may also include a zeolite component in the washcoat to trap or store hydrocarbons otherwise discharged at low temperatures (eg, cold start and engine idle - below 200 degrees Celsius). In embodiments, the zeolite component includes the OC device 14 Zeolite beta (Ti-Beta) and / or zeolite SSZ-33 (Ti-SSZ-33).

The SCR device 18 may include a flow-through metal or a monolithic ceramic substrate wrapped in a fire mat or other suitable substrate that expands when heated to protect and isolate the substrate. The substrate may be packaged in a stainless steel canister or housing that has an inlet and an outlet in fluid communication with exhaust pipes. The substrate may include an SCR catalyst compound applied thereto. The SCR catalyst compound may comprise a zeolite and one or more base metal components, such as e.g. As iron (Fe), cobalt (Co), copper (Cu) or vanadium (V), which act in an efficient manner to NO components in the exhaust gas 15 in the presence of a reducing agent, such as. B. ammonia (NH3) to convert. The zeolite component in the SCR catalyst compound is capable of storing ammonia.

Fine dust filter (PF) 20 may be below the SCR catalyst device 18 be arranged. The PF 20 filters the carbon and other particles from the exhaust gas 15 out. In embodiments, the PF 20 can be made using a ceramic wall flow monolith filter encased in a fire mat or other suitable substrate that expands when heated to protect and isolate the substrate. The filter may be in a stationary canister or housing made of, for example, stainless steel and having an inlet and an outlet in fluid communication with exhaust pipes. The ceramic wall flow monolith filter may have a plurality of longitudinal channels defined by longitudinal walls. The channels include a subset of inlet channels having an open inlet end and a closed outlet end, and a subset of outlet channels having a closed inlet end and an open outlet end. The exhaust gas entering the filter through the inlet ends of the inlet channels 15 is forced to pass through the adjacent longitudinal walls in the outlet channels. By way of this exemplary wall-flow mechanism, carbon (soot) and other particles become exhaust gas 15 filtered out. The filtered particles deposit on the longitudinal walls of the intake ports and over time cause the exhaust back pressure on the engine to increase 12 , The accumulation of particulate matter within the PF 20 is regularly removed by cleaning or regeneration to reduce the back pressure. Regeneration involves the oxidation or burning of accumulated carbon and other particulate matter at a normally high ambient temperature (> 600 ° C).

The OC device 14 , the SCR device 18 and the PF 20 may have a respective selected operating temperature at which the device effectively and efficiently removes particulate matter or the exhaust gas 15 transforms. For example, the SCR device has 18 an operating temperature for absorbed exhaust gas 15 in which the device converts NO to N ₂ at the selected or higher temperature. In addition, the OC device can 14 be used to burn HC in an exothermic reaction, which in the PF 20 Accumulated particulate matter burns effectively. The introduction of the PF 20 Regeneration usually occurs at a selected operating temperature, wherein an exothermic reaction is caused by a high exhaust gas temperature, which burns or oxidizes the accumulated particulate matter.

At engine start, the exhaust aftertreatment devices may have ambient temperature, which is typically too low for the operation of the devices. In addition, the temperatures of the exhaust aftertreatment devices may not always be above their respective operating temperatures, depending on the engine operation. The temperatures of the exhaust aftertreatment devices are therefore increased, if necessary, by raising the exhaust gas temperature. In embodiments, the HC injector injects 30 additional fuel above the OC device 14 so that the fuel in the OC device 14 burns to increase the exhaust gas temperature temporarily. Alternatively, or in conjunction therewith, a post-injection strategy may be employed to increase the exhaust gas temperature by injecting additional fuel into the cylinder (s) of the engine 12 temporarily increase.

A control module (or a controller) 22 controls the engine 12 and / or one or more exhaust components based on the collected and / or modeled data. The data can be from multiple sensors 24 . 26 , and 28 the exhaust aftertreatment system 10 be received. In various embodiments, the acquired and / or modeled data includes exhaust temperature, exhaust flow data, soot loads, NOx concentrations, exhaust constituents (chemical composition), pressure differences, and many other parameters. In embodiments, the sensors are 24 - 28 at various points of the exhaust aftertreatment system 10 arranged. To simplify the description it is assumed that the sensors 24 capture or model the above parameters, and that it is the ones above and below the OC device 14 arranged sensors 26 and 28 are temperature sensors that detect the respective exhaust gas temperature above and below the OC device.

The control module 22 serves to select processes or operations based on the collected and / or modeled data, such as B. the diagnosis of the OC device 14 to perform. In embodiments, the control module provides 22 determines if the OC device 14 based on the determination of whether the temperature difference between inlet and outlet of the OC device 14 has a rise in temperature, is working properly. More specifically, the control module provides 22 determined that the OC device 14 works properly if the differential temperature has a temperature rise. Otherwise, the control module stops 22 determined that the OC device 14 not working properly. In embodiments, the presence of a temperature rise in the differential temperature is interpreted to mean that the zeolite component of the OC device 14 as expected, stores hydrocarbons.

It should be noted that the exhaust aftertreatment system 10 not on the in 1 illustrated configuration should be limited. For example, the exhaust aftertreatment devices 14 - 20 be arranged in the exhaust aftertreatment system in an order that differs from the illustrated order of the OC device 16 , the SCR device 18 and the PF 20 different. For example, the SCR device 18 below the PF 20 be arranged. In addition, more, fewer, or different exhaust aftertreatment devices may be in the exhaust aftertreatment system 10 be arranged. For example, the SCR device and the PF 20 be configured as a single device (eg in a single canister). As another example, another OC device may be between the SCR device 18 and the PF 20 be arranged. In this case, additional sensors between the additional OC device and the PF 20 to be placed.

In a consideration of 2 It should be noted that a data flow diagram various embodiments of the control module 22 the exhaust aftertreatment system 10 out 1 illustrated. Various embodiments of the control module 22 According to the present disclosure, any number of sub-modules may be included. As can be seen, the in 2 submodules shown combined and / or further subdivided. Entries in the control module 22 can from the sensors 24 - 28 out 1 , as well as other sensors (not shown) within the vehicle 32 are received, received from other control modules (not shown), and / or from other sub-modules (not shown) within the control module 22 determined / modeled. In various embodiments, the control module includes 22 in addition to further (not shown) sub-modules, a fuel injection control module 202 , a temperature determination module 204 , an exothermic analysis module 206 , a message module 208 , as well as a parameter archive 210 ,

The parameter archive 210 stores various parameters of the vehicle 32 , These parameters include z. B. operating parameters of the exhaust aftertreatment devices of the exhaust aftertreatment system 10 , The submodules of the control module 22 use the parameters to detect and generate various control signals. The in the parameter archive 210 stored parameter values may be through the submodules of the control module 22 or other modules of the vehicle 32 specified or updated dynamically.

The fuel injection control module 202 determines that above the OC device 14 injected HC content, as well as the injection time. In embodiments, the fuel injection control module determines 202 based on a number of different parameters of the vehicle 32 the HC fraction to be injected. Among the parameters that the fuel injection control module 202 used to determine the HC content include the proportions and ages of various oxidation catalyst compounds of the OC device 14 , as well as other operating parameters (eg, size, composition, etc.) of the OC device 14 , The amount of fuel determined for injection is determined by the exothermic analysis module 206 used to determine, as described below, whether the OC device 14 works properly. The fuel injection control module 202 generates and sends to inject the HC into the engine 12 one or more control signals 224 to the HC injector 30 and / or the fuel injector.

In embodiments, the fuel injection module monitors 202 the temperature 212 , which is the temperature above the OC device 14 or the temperature of the OC device 14 can act. If the temperature 212 a threshold temperature (eg, the operating temperature of the OC device 14 ), controls the fuel injection module 202 for injecting the fuel into the engine 12 the HC injector 30 and / or the fuel injection module to control the HC in the exhaust gas above the OC device 14 to increase in the determined HC content. The increased HC content flows into the OC device 14 , The temperature 212 can during a cold start of the engine 12 or idling the engine 12 stay below the threshold temperature or fall below it.

The differential temperature determination module 204 receives the inlet temperature 214 or the temperature above the OC device 14 from the sensor 26 , as well as the outlet temperature or the temperature below 216 the OC device 14 from the sensor 28 , In embodiments, the differential temperature determination module determines 204 the differential temperature throughout the OC device 14 by keeping the upper temperature 214 from the lower temperature 216 subtracted. That is, the differential temperature throughout the OC device 14 matches the heat generated by that in the OC device 14 burned HC is generated. The difference temperature 218 throughout the OC device 14 is sent to the exothermic analysis module 206 output.

The exothermic analysis module 206 Determines if the OC device 14 based on the difference temperature 218 works properly. Specifically, it provides the exothermic analysis module 206 in embodiments, that the OC contraption 14 works properly if the differential temperature 218 has a temperature rise after the fuel injection control module 202 determined amount of fuel above the OC device 14 is injected. If the difference temperature 218 has no increase in temperature, provides the exothermic analysis module 206 determined that the OC device 14 not working properly.

As described above, the zeolite component stores the OC device 14 Hydrocarbons when the OC device 14 not enough is heated to the exhaust in the OC device 14 to burn the flowing HC. When the temperature of the OC device 14 reaches an ignition temperature, the HC is passed through the zeolite component of the OC device 14 dissolved and starts to burn and therefore produces a temperature rise in the differential temperature in the entire OC device 14 , Once the zeolite component of the OC device 14 during aging of the OC device 14 used up or sintered, indicates the temperature throughout the OC device 14 a lower temperature rise and ultimately no increase in temperature at all. The exothermic analysis module 206 determines the proper operation of the OC device 14 based on whether the differential temperature indicates that the zeolite component of the OC device 14 one as a temperature rise in the differential temperature 218 manifested expected hydrocarbon fraction stores.

3 shows two temperature curves of the differential temperature within an OC device as a graph 302 and 304 , More precisely, it is diagram 302 a temperature profile of an OC device that has no zeolite component or whose zeolite component is used up. At diagram 304 it is a temperature profile of an OC device whose zeolite component stores hydrocarbons as expected. The X-axes of the diagrams show the respective inlet temperatures and temperatures above the OC devices, respectively, and the Y-axes of the diagrams show the respective outlet temperatures and temperatures below the OC devices, respectively. As shown, the graph indicates 304 indicates that the differential temperature throughout the OC device should experience a temperature increase when the zeolite component of the OC device stores HC at low temperatures.

While the engine is in operation and exhaust 15 to the OC device, the temperatures of the OC device (ie, the inlet and outlet temperatures of the OC device) should increase. The outlet temperatures are due to the exothermic reactions that the exhaust gases as through the dotted lines 306. and 308 indicated, oxidize, as expected, always higher than the inlet temperatures. When the temperature of the OC device without zeolite component reaches an operating temperature of the OC device, the differential temperature due to the exothermic oxidation of CO and the unburned HC over the surface of the catalyst element in the OC device increases, as by the double-directional arrow 310 in the diagram 302 hinted at. On the other hand, when the temperature of the zeolite component OC device reaches the operating temperature, the differential temperature has a temperature rise 312 because the zeolite dissolves the stored HC, which begins to burn at an ignition temperature of the HC. That is, a temperature rise of the differential temperature represents the heat generated by the combustion of the HC stored by the zeolite component. In other words, the temperature rise is dependent on the HC content stored by the zeolite component. The differential temperature of the entire OC device remains (ie, the outlet temperature remains higher than the inlet temperature) after the rise, as by the double-headed arrow 314 indicated, the same, since the unburned HC burns in the exhaust gas in the OC device. As with a consideration of 3 determine diagnoses the exothermic analysis module 206 any loss of zeolite by changing the differential temperature 218 with a temperature profile for the OC device 14 compares, which has a temperature rise.

4 illustrates several temperature profiles 402 . 404 and 406 the differential temperatures throughout the OC device with a zeolite component at different ages of the OC device. Specifically, the temperature curve represents 402 the OC device aged for two hours at 600 degrees Celsius in the oven during the course of the temperature 404 an OC device aged for 48 hours at 800 degrees Celsius in the oven, and the temperature profile 406 an OC device that has aged in the oven for 48 hours at 1000 degrees Celsius. It should be noted that the temperature characteristics of a particular OC device correspond to certain configurations - size, capacitance, types of oxidation substrates used, substrate proportions, etc.

In a renewed consideration of 2 it should be noted that the parameter archive 210 different temperature histories we store at different ages of the OC device 14 match, so the exothermic analysis module 206 can diagnose the zeolite loss on the basis of these courses. For example, in embodiments, the exothermic analysis module 206 the Age level of the OC device 14 based on the operating parameters of the OC device 14 determine and choose a temperature course corresponding to the age group. Accordingly, the exothermic analysis module 206 determine if the difference temperature 218 has the temperature rise according to the selected temperature profile.

Those skilled in the art will recognize that there are many different methods that use the exothermic analysis module 206 can be implemented to detect a temperature rise. For example, the exothermic analysis module can be configured to detect a temperature rise without using temperature gradients. As a specific example of the detection of a temperature increase without the use of temperature gradients, it is stated that the exothermic analysis module 206 is able to determine if the outlet temperature of the OC device 14 exceeds a threshold temperature (eg, 40 degrees Celsius) when the inlet temperature of the OC device 14 within a certain temperature range (for example, 200 to 250 Degrees Celsius).

Once the exothermic analysis module 206 determines if the OC device 14 works properly, gives the exothermic analysis module 206 the operating status 220 (ie, proper or improper) of the OC device 14 to the message module 208 out. Based on the status 220 sets the message module 208 the value of a diagnostic error code (DTC) associated with the OC device 14 fixed and communicates the code. In various embodiments, the diagnostic code may be generated by generating a message 222 a serial data bus (not shown) of the vehicle 32 communicated with the message 222 to a remote location using a telematics system of the vehicle 32 transmitted or by a technician tool connected to the vehicle 32 can be retrieved. The exothermic analysis module 206 can the status 220 to a module that controls an in-vehicle display to the driver 32 about the operational status of the OC device 14 to notify.

In a consideration of 5 and 1 and 2 It should be noted that a flowchart illustrates a method for determining the proper functioning of an OC device 14 illustrated. In various embodiments, the method may be performed by the control module 22 out 1 and 2 according to the present disclosure. As can be seen from the disclosure, the sequence of operations within the methods is not as in 5 is limited to sequential processing, but may be implemented, as appropriate, in one or more different orders according to the present disclosure. In various embodiments, the method may be based on predefined events and / or continuously during operation of the engine 12 be executed.

In an example, the method at block 500 kick off. At block 505 monitors the control module 22 the inlet temperature 214 , as well as the outlet temperature 216 the OC device 14 , In embodiments, the control module determines 22 the difference temperature 218 based on the inlet and outlet temperatures 214 and 216 the OC device 14 ,

At block 510 determines the control module 22 optionally one above the OC device 14 injected HC-share, as well as the time of injection. In embodiments, the control module uses 22 a series of operating parameters of the OC device 14 to determine the amount of fuel to be injected and the timing of the injections. The control module 22 can be used to inject the fuel into the engine 12 generate one or more control signals and to the HC injector 30 and / or send the fuel injector.

At block 515 determines the control module 22 optionally, whether the differential temperature in the entire OC device 14 Is zero or within a threshold difference of zero when the inlet temperature of the OC device 14 is relatively high (eg 250 degrees Celsius). If it is determined that the differential temperature in the entire OC device 14 Zero or within a threshold difference of zero, the control module goes 22 continue to block 520 to determine that the OC device 14 not working properly yet. More specifically, the control module provides 22 determines if the OC device 14 does not properly perform its HC and CO conversion operations and its NO conversion operation.

If the control module 22 at block 515 determines that the differential temperature throughout the OC device 14 neither zero nor within the threshold difference of zero, the control module goes 22 continue to block 525 to determine whether the difference temperature is a temperature rise corresponding to a temperature profile of the OC device 14 in the age group. If the differential temperature has a temperature increase, the control module goes 22 continue to block 530 to determine that the OC device 14 works properly (for example, that the zeolite component of the OC device 14 stores the HC in the exhaust gases). If the differential temperature has no temperature rise, the control module goes 22 continue to block 535 to determine that the OC device 14 not working properly (for example, that the zeolite component of the OC device 14 does not store the HC in the exhaust gases).

At block 540 partly the control module 22 the operational status of the OC device 14 With. In embodiments, the control module creates 22 a diagnostic trouble code (DTC) for the OC device 14 which can be remotely transmitted via a telematics system or retrieved by a technician tool. If necessary, the process ends at block 545 ,

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and the particular parts may be substituted with corresponding other parts without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular material situation to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the specific embodiments disclosed, but that it also encompass all embodiments falling within the scope of the application.

Claims (10)

 A method of diagnosing an oxidation catalyst (OC) device of an exhaust aftertreatment system, comprising: Monitoring a differential temperature throughout the OC device; Determining, by a control module of the exhaust aftertreatment system, whether the differential temperature has a temperature rise; and Determining that the OC device is functioning properly in response to determining that the differential temperature has a temperature rise.  The method of claim 1, further comprising determining that the OC device is not functioning properly in response to determining that the differential temperature has no temperature rise.  The method of claim 2, further comprising creating a message indicating whether the OC device is functioning properly.  The method of claim 3, further comprising connecting at least one telematics system and a technician tool to retrieve the message.  The method of claim 1, wherein the OC device includes a zeolite component for storing hydrocarbons before the temperature of the OC device reaches an operating temperature of the OC device.  The method of claim 5, wherein a temperature rise in the differential temperature indicates that the zeolite component of the OC device stores hydrocarbons.  The method of claim 5, wherein the differential temperature without temperature increase indicates that the zeolite component does not store the expected hydrocarbon content.  Diagnostic system comprising: an oxidation catalyst (OC) device in an exhaust aftertreatment system of a vehicle; and a control module configured to do the following: Monitoring a differential temperature throughout the OC device; Determining whether the differential temperature has a temperature rise; and Determine that the OC device in response to the finding that the Temperature difference has a rise in temperature, working properly. The diagnostic system of claim 8, wherein the control module further functions to determine that the OC device is not functioning properly in response to determining that the differential temperature has no temperature rise. The diagnostic system of claim 9, wherein the control module further functions to generate a message indicating whether the OC device is functioning properly.

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